1. Technical Field
The present invention relates to a simulation system, simulation apparatus, and simulation method that perform propagation simulation regarding the radio wave quality of base station radio waves.
2. Background Art
In mobile communications networks, in order to identify an area in which a mobile terminal can communicate, for example, propagation simulation regarding radio wave quality such as the field intensity of base station radio waves sent from a base station is performed by a simulation apparatus. For example, see, JP2003-070050A.
The simulation apparatus acquires measured results of the radio wave quality of the base station radio waves in a specific area, and corrects a propagation equation used for propagation simulation using the measured results for performing propagation simulation in the specific area. At this time, the propagation equation is corrected using the measured results of the radio wave quality at a plurality of positions, so that highly accurate propagation simulation can be performed in which the effect that is caused by the natural features of the landscape is reflected.
As a method of acquiring measured results of radio wave quality at a plurality of positions by the simulation apparatus, there is a method in which measured results are acquired from a vehicle used for acquiring measurements, in which the vehicle measures radio wave quality at a plurality of positions while running in fields. However, in this method, it is necessary that the vehicle used for acquiring measurements run in fields, causing a problem that takes time and effort.
As another method, there is a method of acquiring measured results from a plurality of individual mobile terminals, each of which measures its own radio wave quality at a position at which the terminal exists.
However, a problem arises in which the propagation equation, in which the effect that is caused by the natural features of the landscape is reflected, is not corrected and propagation simulation cannot be performed highly accurately unless radio wave quality is measured at a plurality of positions under the same conditions.
For example, in the case where radio wave quality is measured indoors, the measured result includes transmission loss caused by a building. In addition, transmission loss caused by a building varies depending on the structure of the building or a position inside the building. Because of this, in the case where radio wave quality is measured at a certain position in the inside of a building, measurements are performed under different conditions between that position and another position.
Thus, for correcting the propagation equation, it is necessary to use only the measured result of radio wave quality outdoors.
In the above-mentioned method of acquiring the measured results of radio wave quality from the mobile terminals, the measured results are acquired regardless of differentiation between mobile terminals located indoors or outdoors. For this reason, even though the propagation equation is corrected using the measured results as they are, highly accurate propagation simulation cannot be performed.